Added the ability to enable filters to work with empty values (#200)

* Added the ability to enable filters to work with empty values

* update tests and filter before input is set instead of adding methods

---------

Co-authored-by: Eric Tucker <[email protected] Eric Tucker>

Author: james-waring

src/ModelFilter.php

@@ -41,6 +41,13 @@ abstract class ModelFilter
      */
     protected $blacklist = [];
 
+    /**
+     * Filter out empty input so filter methods won't be called with empty values (strings, arrays, null).
+     *
+     * @var array
+     */
+    protected $allowedEmptyFilters = false;
+
     /**
      * Array of input to filter.
      *
@@ -93,8 +100,9 @@ abstract class ModelFilter
     public function __construct($query, array $input = [], $relationsEnabled = true)
     {
         $this->query = $query;
-        $this->input = $this->removeEmptyInput($input);
+        $this->input = $this->allowedEmptyFilters ? $input : $this->removeEmptyInput($input);
         $this->relationsEnabled = $relationsEnabled;
+
         $this->registerMacros();
     }
 

tests/ModelFilterTest.php

@@ -288,6 +288,27 @@ public function testBlacklistAddingAndRemoving()
         $this->assertFalse($this->filter->methodIsBlacklisted($method));
     }
 
+    public function testAllowedEmptyFilter()
+    {
+        $emptyInput = [
+            'empty_array' => [],
+            'null_value' => null,
+            'empty_string' => '',
+        ];
+
+        $filter = new class($this->builder, $emptyInput) extends ModelFilter
+        {
+            protected $allowedEmptyFilters = true;
+        };
+
+        $this->assertEquals($filter->input(), $emptyInput);
+
+        $filter = new class($this->builder, $emptyInput) extends ModelFilter {
+        };
+
+        $this->assertEquals($filter->input(), []);
+    }
+
     public function testParentClassMethodsCantBeCalledByInput()
     {
         $badMethod = 'whitelistMethod';